(a) Technical Field
The present disclosure of invention relates to an organic light emitting diodes display.
(b) Description of Related Technology
A typical organic light emitting diodes display comprises light emitting elements each including two electrodes and an organic emitting layer positioned therebetween. Electrons injected from one of the electrode and holes injected from the other electrode combine with one another in the organic emitting layer to form an exciton, and light is emitted when the exciton discharges energy (e.g., in the form of photons).
The organic light emitting diodes display (OLEDD) includes a plurality of pixels each including one or more organic light emitting diodes that are each a self-light emitting element. The OLEDD typically further includes a plurality of thin film transistors (TFT's) for driving the one or more organic light emitting diodes are formed in each pixel and at least one capacitor for storing a drive level voltage. The plurality of thin film transistors typically includes a switching (OLED-addressing) thin film transistor and an OLED driving thin film transistor.
The switching thin film transistor includes a respective gate insulating layer having a relatively small thickness for the space between a gate electrode and a semiconductor layer for thereby providing a rapid switching operation. On the other hand, the OLED driving thin film transistor has a respective and relatively thicker gate insulating layer that broadens the interval between its driving gate electrode and corresponding driving semiconductor layer in order to be able to handle a broader driving range of gate voltages applied to the gate electrode of the driving thin film transistor.
In one class of embodiments, two gate insulating layers are positioned between the driving gate electrode and the driving semiconductor layer of the OLED driving thin film transistor. A problem with this configuration is that current scattering (mass production current deviation) of the driving thin film transistor may occur due to capacitance scattering associated with the two gate insulating layers.
It is to be understood that this background of the technology section is intended to provide useful background for understanding the here disclosed technology and as such, the technology background section may include ideas, concepts or recognitions that were not part of what was known or appreciated by those skilled in the pertinent art prior to corresponding invention dates of subject matter disclosed herein.